title: Different characteristics of human herpesvirus 6 encephalitis between primary infection and viral reactivation.
abstract: BACKGROUND
  Pathogenesis of human herpesvirus 6 (HHV-6) encephalitis, in particular difference between HHV-6 encephalitis at the time of primary infection and reactivation remains unclear.
  
  
  OBJECTIVE
  To elucidate the mechanism of HHV-6 encephalitis at the time of primary infection and reactivation.
  
  
  METHODS
  Twenty-two HHV-6 encephalitis patients at the time of primary infection, 6 febrile convulsion (FC) patients caused by HHV-6 infection, and 14 FC patients without HHV-6 infection (non HHV-6 FC) were enrolled. Additionally, 7 stem cell transplant recipients with HHV-6 encephalitis and eight adult controls were also enrolled in this study. Cerebrospinal fluid (CSF) HHV-6 DNA copy numbers and biomarkers levels were compared.
  
  
  RESULTS
  Low copy number of CSF HHV-6 DNA was detected in 7 of the 22 patients with HHV-6 encephalitis in primary infection, whereas all seven CSF samples collected from post-transplant HHV-6 encephalitis patients contained high viral DNA copy numbers (P<0.001). CSF concentrations of IL-6 (P=0.032), IL-8 (P=0.014), MMP-9 (P=0.004), and TIMP-1 (P=0.002) were significantly higher in patients with HHV-6 encephalitis in primary infection than non-HHV-6 FC. CSF IL-6 (P=0.008), IL-8 (P=0.015), and IL-10 (P=0.019) concentrations were significantly higher in patients with post-transplant HHV-6 encephalitis than adult controls.
  
  
  CONCLUSIONS
  The present study suggests that the characteristics of HHV-6 encephalitis are different between HHV-6 encephalitis at the time of primary infection and reactivation in transplant recipients.
authors.affiliation: Department of Pediatrics, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 4701192, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Kawamura
authors.forename: Ken
authors.initials: K
authors.lastname: Sugata
authors.forename: Masaru
authors.initials: M
authors.lastname: Ihira
authors.forename: Takateru
authors.initials: T
authors.lastname: Mihara
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Mutoh
authors.forename: Yoshizo
authors.initials: Y
authors.lastname: Asano
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Yoshikawa
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000134:cerebrospinal fluid; D016022:Case-Control Studies; D002675:Child, Preschool; D004279:DNA, Viral / Q000134:cerebrospinal fluid; D018792:Encephalitis, Viral / Q000134:cerebrospinal fluid / Q000821:virology*; D005260:Female; D015654:Herpesvirus 6, Human / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D007223:Infant; D007378:Interleukins / Q000134:cerebrospinal fluid; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000134:cerebrospinal fluid; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012008:Recurrence; D019349:Roseolovirus Infections / Q000134:cerebrospinal fluid / Q000821:virology*; D003294:Seizures, Febrile / Q000821:virology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000134:cerebrospinal fluid; D014180:Transplantation / Q000706:statistics & numerical data; D014775:Virus Activation
chemical_list: D015415:Biomarkers; D004279:DNA, Viral; D007378:Interleukins; D019715:Tissue Inhibitor of Metalloproteinase-1; D020780:Matrix Metalloproteinase 9